I hear what you're saying, but unfortunately the age of the car doesn't affect the cost of producing an all new part for it. It may sound crazy, but you're better off paying a fair price for newly developed parts for the car, since it will afford the company producing them to make more parts available to you.
Part of the reason the Protege market has died off is because many businesses couldn't afford to continue to produce parts from them and pay their bills, so they turned their efforts elsewhere.
I'm very cautious myself, to be honest.